With the fast development of the computer technology, more and more users are accustomed to completing all kinds of work by using a network which is convenience and abundant of resources. To some extent, time is saved and work efficiency is improved, and further development and perfection of the Internet is enhanced. However, with the development of higher technology, the network has great security vulnerabilities while bringing convenience and entertainment to people. For example, usernames or account numbers registered on the Internet of a lot of users might be stolen by other people easily, which would bring economic loss or spiritual loss to the users or related sellers.